I've had this listed in the lost and found for a week, and no one has spoken for it. From the stampings, it would appear to be a 1971 M21 for a buick. It has the 26 spline main shaft and 32 spline output shaft. It has the desireable 661 main case. All bolt holes look in good condition, and from what I can see inside it looks in good condition. I would still disassemble it to be sure. I've owned it for over 30 years, and will probably never use it. When I purchased it, we had a rearend in the back of the truck and it slid and put a hole in the tail housing. It can either be repaired or find another tail housing. I don't think it would be a hard thing to repair. Located in RI. $700 or best reasonable offer plus shipping costs.